How is the traditional waterfall software development lifecycle structured?

The traditional waterfall software development lifecycle is structured in a sequential and gated manner. This model is characterized by its linear approach, where each phase must be completed before moving on to the next one. Phases typically include requirements gathering, design, implementation, testing, deployment, and maintenance.

In this structure, once a phase is completed, it is often considered finished, and returning to a previous phase is usually not easy without significant effort. This gated nature means that each stage has clear deliverables and review points, ensuring that all requirements are met before proceeding.

This approach is in contrast with continuous and flexible models where iterations happen concurrently, and changes can be integrated throughout the process, which is represented by choices that describe more agile methodologies. The waterfall model emphasizes thorough documentation and formal review processes at each stage rather than ongoing collaboration which characterizes iterative or incremental frameworks.